Hyundai Sonata: Engine Control System / Ambient Temperature Sensor (ATS) Description and Operation
Ambient Temperature Sensor (ATS) is installed on the
front-end module and senses the ambient temperature. ECM receives not
only the intake air temperatue but also the ambient air temperature
informations at the same time to control the intake air quantity
precisely provided through the turbo charger. The electrical resistance
of the thermistor decreases as the temperature increases, and increases
as the temperature decreases This sensor has a Negative Temperature
Coefficient (NTC) and its resistance is in inverse proportion to the
temperature.

Inspection
1.
Turn the ignition switch OFF.
2.
Disconnect the IATS connector.
3.
Measure resistance between the IATS terminals 3 and 4.
4.
Check that the resistance is within the speci ...
Specification
Temperature[°C(°F)]Resistance(k?) -40(-40)841.2~1019.3 -20(-4)263.8~306.50(32)92.4~102.810(50)57.0~62.220(68)36.2~38.840(104)15.3~16.750(122)10.3~11.460(140)7.1~8.080(17 ...
Other information:
Hyundai Sonata LF 2014-2019 Service Manual: Repair procedures
Compession Pressure Inspection
If the there is lack of power, excessive oil consumption or poor fuel economy, measure the compression pressure.
1.
Make sure the oil in the crankcase is of the correct
viscosity and at the correct level and that the battery is correctly ...
Hyundai Sonata LF 2014-2019 Service Manual: Air Ventilation Seat Repair procedures
Removal
[Ventilation Blower]
1.
Disconnect the negative (-) battery terminal.
2.
Remove the front seat.
(Refer to Body - "Front Seat Assembly")
3.
Remove the under cover assembly.
(Refer to Body - "Front Seat Cushion Cover")
4.
Remove the blower fan (A) after removing the fixed c ...